Down-draft furnace



2 Sheets-Sheet l IN VEN TOR.

J. R. FELLows DOWN DRAFT FURNCE Filed lay 14, 1943 Defn 23, 1947.

'23, 1947. J. R. rl-ELLows DOWN DRAFT FURNACE Filed lay 14, 1943 2 Sheets-Sheet 2 Patented Dec. 23, 1947 Julian Robert Fellows, Urbana,

nl., assigner to' ,The Board off'lrlisteel of the University of Illinois, Urbanmlll.

rAspiration my 14, 194s, serial No. 486,940 a claims. (ci. 11o- 24) This invention relates to down-draft furnace construction, particularly in furnaces adapted tol burn solid fuels, especially bituminous coal and similar fuels, to the best advantage and without substantial smoke loss.

An object of this invention is to provide in a down-draft furnace for the efcient supplying of secondary air in a furnace of the general type shown in U. S. Letters Patent No; 2,295,781, is-

sued September 15, 1942, in which the furnace is so arranged as to include three-relatively distinct chambers, namely, a coking chamber in which fresh or green coal is converted into coke,

a coke burning chamber in which the coke burns as a smokeless fuel while a new charge of coal is being coked in the coking chamber, and a combustion chamber in which the gases generated during the coking of the coal and the burning of the coke are consumed.

In such a construction it is desirable and it is an object of this invention to provide durable, efcient means for separating the several chambers and conducting secondary air in the proper proportion to the upper portion of the coke burning, chamber. 'I'his may be done, as in the case 2 Other objects and advantages of the invention will readily appear from the description ofthe invention.

of the above mentionedpatent, by providing a baffle wall with a secondary air passage therein in communication with the atmosphere. In making such provision' it is of course necessary to correlate the cross-sectional area of the secondary air passage with the dimensions of the several chambers or zones of combustion and the supply of primary air. In the present invention this is accomplished in part by providing a sectional baiiie wall and combustion chamber construction, which may be oi plastic, tile, brick or other suitable material capable of withstanding the required temperatures and variations of temperature, and being preformed may be made to specifications in mass production.

The present inventionhas important advantages over other forms of construction, namely,

simplicity, compactness, durability, adaptability V to quick, accurate installation, and low cost.`

These advantages are of especial importance in view of present day war time restrictions upon the use ofessential materials, entailing dimensional limitations as well as the elimination of non-essential details of construction, and the substitution of the more abundant for the scarce materials.

It is also an object of this invention to provide 1 in such a furnace means for exhausting smoke and gases from the coking chamber preliminary to opening of the furnace door.

, This inventionffurther resides in the combination, construction andv arrangement of parts illusv vtrated in'the accompanying drawings, and while there is shown therein preferred embodiments of the invention, it is to be understood that the same are susceptible of modincation and change without departing from the spirit of the invention.'

The accompanying drawings illustrate a selected embodiment of the invention, and the views therein .are as follows:

Fig. 1 is a vertical sectional view of a furnace embodying the invention.

Figs. 2 and 3 are perspective views of sections of the combined baille wall and combustion chamberconstruction of the invention.

Fig. 4 is a perspective view of an assembly of l the sections shown in Figs. 2 and 3. Fig. 5 is a sectional view along the line 5--5 of Fig. 4. y

Fig. 6 is a perspective view of a modification of the invention. l

Fig. 7 is a sectional view. similar to that of Fig. 5, showing a construction employing the form of Fig. 6 in combination with the sections shown in Figs. 2 and 3.

Fig. 8 is a detail plan view of -a portion of the invention' shown in Fig. 1.

In the embodiment of the invention shown in Fig. 1 of the drawings the down-draft furnace II comprises a closed shell or casing I2 having an upper front opening or fuei inlet Il and a closure ordoor Il therefor, and a rear opening or gas outlet I 5.

, A furnace body I6 is mounted within the casing I2, as uponsupporting brackets I'I and I8 secured to the side walls of the casing adjacent the bottom thereof. The walls of the body I6 are generally spaced from the walls of the casing a suitable distance to provide an air space I0 therebetween. The lower front portion of the body I6 is arranged to provide a cleanout opening 20 for the removal of ashes. This opening is common to the body and casing, the body being shaped for the purpose adjacent the opening,which has a closure or door 2| suitably mounted in the casing.l

Grates 22 and 23iare mounted within the body I6 in spaced relation with the bottom wall or floor 24 thereof. The grate 22 is a stationary grate having suitably spaced air holes 22a and is disposed at an angle, which may be of the -order of 45", with its in the front wall'of the body.

forward, upper edge supported upon the edge 25 of an opening provided The lower edge of the grate 22 is supported by an angle bar 26 which is secured at its ends to opposed walls of the body. The grate 23 is preferably of the shaker type and normally is horizontally disposed and pivotally mounted at itsopposed ends on adjacent walls of the body. The grate-,23 is provided with va pull-out shaker member 28 which is pivotally connected at one end to an extension 29 of the grate and extends outwardly of the furnace.

The furnace I I is provided with a chute portion 39 in the front wall of the body adjacent the Iower edge of the opening I3. This chute extends and is preferably lined from the opening I3 to the upper edge of grate 22 with refractory material 6r rebrick 30a.. YThe arrangement of the chute 30 and the vgrate 22 is such as to provide a general slope suitable to permit the ready ad- Vance of a charge of fuel from the region adjacent the opening I3 to the grate 23.

The inner wall of the body IB is provided with an angular support 3I for a. refractory lining 32 above the level of the upper surface of the grate 23. This lining may consist of a tier of rebrick or other suitable material. kUpon the lining 32 the rear edges of sectional members 33 and 34 are supported and so arranged as to form a combustion chamber 35 and a secondary air passage or channel 36. i

The members 33 and 34 comprise integral generallyl rectangular sections of' E-shaped crosssection, preferably of refractory material, with open or cut-away portions31. 38 and 39. The members 33 and 34 are conversely formed so as to iit together' in complementary fashion to form a double tubular structure as shown in Figs. 4 and Y 5. The purpose of the offset portion or ledge 40 formed by cutting away the portions 39 will ary air passages and combustion chambers instead of arranging the members 33 and 34 as shown in Figs. 4 and 5 an intermediate member 4I may be used. This member combines the forms of the members 33 and 34 in back-to-back arrangement so to speak,` and may be interposed between them to provide the multiple passages and chambers of the structure 42 illustrated in Fig. '7. The employment of the member 4I in such an arrangement permits a considerable saving of material and space in that the web portions 43 need be only half as thick as would be the case if the structure were formed by putting together two of the structures of Fig. 4.

The furnace II has a double roof 44 extending rearwardly from .the front of the casing I2 disposed relatively above the opening I3. The roof 44 comprises an upper plate 45 having opposed angular portions or flanges 46 and 41, respectively, at opposite edges, .the outer flange being secured to the casing I2 by means of bolts'48 or other suitable means, as by welding, and the inner flange 41 being adapted to abut a portion of the surface of the members 33 and 34 and member 4I when it is used. The roof 44 also comprises a. lower plate 49 which is arranged'in spaced relation with the plate 45. The plate 49 is secured adjacent one of its edges by means of bolts 59 to the angular flange portion 5I of the casing I2. Adjacent its inner edge the plate 49 is provided with an `angular ange portion 52 adapted to 4 abut an adjacent surface of .the members 33 and 34. and the member 4I when it is used, in spaced relation with the abutment of the ange 41. 'Ihe configuration of theplates 45 and 49 and their arrangement with respect to the members 33 and 34 and .the member 4I when it is used, are such that the plates will assist in maintaining the members in supported position as shown in Fig. l.

The placing of the plates 45 and 49 and the flanges 41 and 52 is such as to provide a suitable air passage 53 in communication with the atmosphere through openings 54 provided in the casing I2 and with the air passages 38 through the space 55 provided "by the offset or cutting away of the portion 39 ofthe members 33. 34 and 4I. Regulation of the admission of air through the openings 54 may be` provided by means of a plate 63 having suitably spaced openings and slidably mounted on .the casing I2 adjacent said openings.

In order to provide for the escape of gases from the lcolring chamber preliminary to opening the furnace door, aligned openings 51 and 51a are provided in the plates 45 and 49, respectively, and connected by a suitable flue 58. A slidable closure 59 for this flue is arranged in guides 60 mounted on the plate 45. The closure 59 is controlled by shaped pull-out member- 6I extending through a suitable opening in the casing I2 and connected at one end with the closure. Movement of the member 6I is limited by the guides 60 and by the provision in the member itself of a measured oiset portion 62.

In constructing a furnace in accordance with the present invention, the roof 44 being first installed, the members 33, 34 and 4I will be set in position with adjacent surfaces abutting the flanges 41 and 52 and temporarily supported. The members 32 will then .be put in place below them.

The ue 58 is preferably connected or formed integrally with .the plate 45 adjacent the opening 51. The opening 51a in the plate 49 is arranged so that upon removal of the bolts the plate 49 may be movedu forwardly so as to disengage the flange 52 fromthe members 33, 34 and 4I. The members 33, 34 and 4I may be made with a beveled edge 69 at the upper rear corner and proportioned with respect to the vertical distance from the upper edge of members 32 to the lower edge of fiange 41 so that upon shifting the plate 49 forwardly the members 33, 34 and 4I may be removed and replaced without moving any of the members 32. In this connection, slots 50a for receiving the bolts 59 may be provided in the plate 49 whereby the position of the plate 49 may be adjustable with respect to the flange 5I.

Above the roof 44 within the body I6 an auxiliary combustion chamber 64 ls provided in communication with the flue 58 when damper 59 is open and with the chamber 35 at all times. The chamber 64 is provided .with openings 65 in communication with radiators 66 and outlet I5.

Air is admitted to the furnace through openings 61 and 68 in the doors I4 and 2|, respectively, in such quantities as may be needed. These openings may be adjustable for various fuels, but the adjustment having been determined for a given fuel, it should remain unchanged to provide for the admission of relatively fixed quantities of air. The configuration and arrangement of openings for the admission of air, the proportioning of quantities of air admitted to the several chambers, and the relative proportions of theseveral chambers and parts generally may be as described in the above-mentioned patent.

It will be readily appreciated that the employment of the sectional members 33, 34 and 4| in a furnace construction of the type described not only simplifies the construction of the furnace, but in addition to enhancing the efficiency of operation of the structure permits an appreciable saving of space by making it unnecessary to provide supplemental insulation for the combustion chamber, as the walls of these members afford adequate insulation therefor.

Changes may be made in the form, construe tion and arrangement of the parts without departing from the spirit of the invention, and the right is hereby reserved to make all such changes as fairly fall within the scope of the following claims. v

The invention is hereby claimed as follows:

1. A4 down-draft furnace comprising means forming a chamber, an outlet from said chamber for gases of combustion, a removable sectional unit disposed within said chamber and dividing said chamber into a coking chamber and a cokeburning chamber adjacent to said coking chamber, means for introducing primaryair into said coke-burning chamber, said unit comprising means forming a combustion chamber within said unit adjacent to said coke-burning chamber and in communication with said cokeburning chamber, and said outlet, and said unit also including means communicating with said coke-burning chamber for introducing secondary air to said coke-burning chamber.

2. A down-draft furnace as set forth in claim 1 wherein the unit includes means forming a plurality of combustion chambers and a plurality of means for introducing secondary air fto the cokeburning chamber, with all said means being within the single unit.

3. A down-draft furnace comprising means forming a coking chamber and a coke-burning chamber adjacent to and in communication with one another, means for introducing primary air into the coke-burning chamber, an outlet for gases of combustion from the furnace, a removable sectional unit in the furnace, said unit comprising means forming a combustion chamber .within said unit adjacent the coke-burning chamlber and in communication with the said cokeburning chamber and the said outlet, and the said unit also including means in communication with the said coke-burning chamber for introducing secondary air to the portion of said coke-burning chamber adjacent the combustion chamber.

4. A double channeled element of fire resistant refractory material, substantially rectangular in cross-section, said element having elongated parallel walls defining a, pair of open channels extending side by side from end to end of the walls, one of said channels being substantially narrower than the other, .fthe walls about the narrower channel terminating substantially short of one end of the element to provide a shouldex` so constructed and arranged as toV facilitate insertion of the element in a down-draft furnace wherein the wider channel forms a combustion chamber and the narrower channel forms a secondary air inlet communicating at the shoulder with a secondary air inlet in the furnace.

5. An element as set forth in claim 4 composed of ceramic material and comprising at least two integrated ceramic members.

6. In a down-draft furnace including side walls, a grate, a refractory lining, a door for the insertion of coal, an air inlet beneath the grate, a secondary air inlet above the grate, a roof having a. downwardly depending iiange, and a flue; a removable element of refractory material having parallel walls defining a pair of channels extending from :top to bottom of the walls, one of said channels forming a combustion chamber communicating with the flue at its top and with the air inlet at its bottom, the other channel being substantially narrower and connecting with the secondary air inlet at its top and terminating adjacent the base of the combustion chamber,

the rear base of the element resting by gravity upon the refractory lining of the furnace and o the top of the element being supported by said the space between the flanges defines the secondary air inlet and each of said flanges supports a wall of the refractory element.

8. A down-draft furnace comprising means forming a, chamber, an outlet from said chamber for gases of combustion, -a removable sectional unit disposed within said chamber and dividing said chamber into a coking chamber and a cokeburning chamber adjacent said coking chamber, means for introducing primary air into said cokeburning chamber, said unit comprising means forming a combustion chamber adjacent to said coking chamber and in communication with said coke-burning chamber and said outlet, and said unit also including means communicating with said coke-burning chamber for introducing secondary air to said coke-burning chamber, and ,means forming a passageway communicating with the coking chamber and the outlet for permitting the escape of gases from the coking chamber.

JULIAN ROBERT FELLOWS.

REFERENCES CITED The following references are of record in the file 'of this patent:

UNITED STATES PATENTS Number Name Date 51,649 Cox Dec. 19, 1865 228,061 Gregory May 25, 1880 257,905 Tower May 16, 1882 273,661 Zell Mar. 6, 1883 659,161 Washburn Oct. 2, 1900 698,902 Budd Apr. 29, 1902 1,781,726 Jewell Dec. 18, 1930 1,807,647 Babb June 2, 1931 1,914,476 Bedard June 20, 1933 2,295,781 Fellows et al Sept. 15, 1942 FOREIGN PATENTS Number Country Date 65,736 Germany Nov. 24, 1892 

